Geranylgeraniol and farnesol, typical members of prenyl alcohol, are believed to be produced in organisms through hydrolysis of geranylgeranyl pyrophosphate and farnesyl pyrophosphate with a phosphatase. Geranylgeranyl pyrophosphate is a pyrophosphate ester of geranylgeraniol, which is yielded by condensation between isopentenyl pyrophosphate and farnesyl pyrophosphate or condensation between three molecules of isopentenyl pyrophosphate and dimethyl aryl pyrophosphate. Geranylgeranyl pyrophosphate is metabolized into a diterpene compound (e.g., gibberellin) by cyclization, into a carotenoid compound via phytoene formed by tail-to-tail condensation, or into polyprenylpyrophosphate by head-to-tail condensation with isopentenyl pyrophosphate. On the other hand, farnesyl pyrophosphate is yielded by condensation between isopentenyl pyrophosphate and geranyl pyrophosphate or condensation between two molecules of isopentenyl pyrophosphate and dimethyl aryl pyrophosphate. Farnesyl pyrophosphate is metabolized into a sesquiterpene compound by cyclization, into steroid and triterpene compounds via squalene formed by tail-to-tail condensation, or into polyprenylpyrophosphate or dolichol by head-to-tail condensation with isopentenyl pyrophosphate. It is also metabolized into a prenylated protein when linked to a cysteine residue of a specific protein such as Ras protein or G protein. Thus, a series of geranylgeraniol derivatives, including geranylgeraniol, geranylgeranyl pyrophosphate and precursors thereof, i.e., farnesyl pyrophosphate, farnesol, geranyl pyrophosphate or geraniol, are dominant compounds as biosynthetic intermediates of terpenes, carotenoids or steroids. In addition, geranylgeraniol and analogous compounds thereof are important for use in the production of perfume, a taxane compound having an anti-tumor activity (Japanese Patent Application No. 8-227481), a hair tonic (Japanese Patent Application No. 8-180449), a therapeutic agent for osteoporosis (Japanese Patent Application No. 9-294089) and the like.
In the production of the geranylgeraniol derivatives stated above, an erg mutant of Saccharoinyces cerevisiae is known to produce and secrete farnesol [Curr. Genet., 18, 41-46 (1990)], but this mutant is not practical for use because it provides a low farnesol production (1 mg/L). Also, there has been developed a technique for producing an arachidonate-containing lipid by culturing a mutant derived from a microorganism having the ability to produce an arachidonate-containing lipid in a medium supplemented with a hydrocarbon, a fatty acid, and/or a fat or oil (Japanese Patent Application Laid-Open (kokai) No. 2000-69987). However, the above supplemental ingredients are only used for conversion into arachidonate (i.e., used as precursors for a final product) or consumed as nutrient sources, and therefore have no effect on extracting a substance produced in the mutant cells.
To produce an useful substance, it is often advantageous to use an elevated energy level for synthesis and an increased concentration of sugar as a starting material. However, when an oily substance is to be produced under an increased sugar concentration, since it has poor permeability through a cell membrane, the oily substance accumulates in cells, thereby inducing product inhibition. In such a case, the oily substance is not expected to be produced at a high yield.